The use of a percussor as an effective device in physical and respiratory therapy is well recognized. A percussor generally has a reciprocating plunger with a rubber cup or similar resilient device at one end which is held against the patient in the area of the body to be treated. Such a device is often used as an alternative or substitute for manual percussion, in which a therapist uses his or her hands against the patient's body in a clapping manner. Percussive devices are shown, for example, in U.S. Pat. Nos. 1,516,717 and 1,796,444. In respiratory therapy, the percussor is held against the patient's chest to mobilize fluids which have accumulated in the lungs. Such a device is effectively used in treatment of bronchitis and similar lung disorders in which desirable treatment is to assist the patient in coughing up and expectorating fluids and mucus.
A percussor for the treatment of cystic fibrosis has been shown to be useful, such a device being disclosed in U.S. Pat. No. 3,955,563. A stated advantage of the latter device over those of the earlier state of the art percussors is the elimination of the straight mechanical linkage vibration features, which have been indicated as causing injury, especially to children, or other users having rather delicate or fragile bone structure, particularly around the ribs. Although the percussor disclosed utilizes a pneumatic powered plunger, rather expensive electronic or fluidic control valves are incorporated for controlling the rate of air bursts to the plunger to achieve the reciprocating percussor motion.